Reflector for a reflector lamp, lamp and canopy for a lamp

ABSTRACT

A reflector ( 8, 9 ) for a lamp ( 24 ), including at least one reflective surface ( 12 ), the reflector being designed such that the light which is emitted by a luminous element ( 1 ) of the lamp ( 24 ) and reflected at the reflective surface ( 12 ) does not impinge on the luminous element ( 1 ).

FIELD OF THE INVENTION

The present invention relates to a lamp featuring a holding device for aluminous element as well as a housing which, at least partially,surrounds an interior space, the housing having an upper housing partand a lower housing part.

BACKGROUND OF THE INVENTION

Well-known are devices which use a closed lamp system. In thisconnection, a heavy increase of the interior space temperature of thelamp takes place, resulting in a reduction in efficiency of the lamp.The light emanating from the lamp is guided in the desired direction, awide distance being required between the luminous element and thereflector, resulting in an increased overall height of the indirectlamp. The known reflectors featuring parabolically shaped reflectorsegments produce a narrow-angle light distribution but no wide-anglelight distribution which is free of direct glare. This narrow-anglelight distribution gives rise, for example, to an increased reflectionformation on a tabletop.

It is an object of the present invention to provide a lamp with which ahigher efficiency is attained.

SUMMARY OF THE INVENTION

This objective is achieved by a lamp featuring a holding device for aluminous element as well as a housing which, at least partially,surrounds an interior space, the housing having an upper housing partand a lower housing part, at least one gap existing between the upperhousing part and the lower housing part through which air exchange ispossible between the interior space of the lamp surrounded by thehousing and the external space.

Because of the air exchange between the interior space and the externalspace through the gap, the inside temperature will increase due tothermal heating only slightly in a region of the lamp whereby aconsiderably higher efficiency of the luminous element is attainedcompared to the known closed lamps in whose interior there exists anovertemperature of up to 30° C. which corresponds to a reduction inefficiency of about 30% at normal room temperature. In particular whenusing a fluorescent lamp because of the thermal heating in a region, thelight output ratio strongly depends on the ambient temperature, that isthe interior space temperature of the lamp. Using a lamp according tothe present invention, it is possible for the reduction in efficiency ofa fluorescent lamp to lie in a range below 5%.

In an advantageous embodiment of the just described lamp according tothe present invention, provision is made for the upper housing part tofeature a first transmitter/reflector and/or for the lower housing partto feature a second reflector which is designed according to one of theembodiments described above. In this manner, the efficiency is furtherincreased since, besides the reduction of the ambient temperature of thefluorescent tube through the gap, a further increase in efficiency isattained with regard to the emitted light since no light reflected bythe reflector is reflected into the luminous element again.

In a further advantageous refinement of the present invention, provisionis made for the housing to have a cylindrical or tubular shape. Ahousing formed in such a manner is particularly easy and inexpensive tomanufacture and suitable for receiving a tubular commercial fluorescenttube.

In another expedient embodiment of the present invention, provision ismade for the upper housing part to be connected to the lower housingpart via connecting means, the upper housing part and/or the lowerhousing part being preferably connected to the connecting means in aneasily detachable manner. In this manner, the specific part can bereplaced very easily, for example, when it is defective or when the userof the lamp wants to use a different part which appears to him to bebetter suited because of aesthetic, illumination or other reasons.

In a further advantageous refinement of the present invention, provisionis made for the connecting means to be arranged at the ends of thehousing. In this manner, the largest possible space is made availablefor an illuminant which is arrangeable in the lamp.

Moreover, the connecting means can engage best with the housing at theend thereof, and can also be accessed best there, thus enabling easyreplacement.

In a further expedient embodiment of the present invention, provision ismade for the connecting means to have noses which engage with the upperhousing part and/or with the lower housing part, forming a positivelock. In this manner, a simple but secure connection between the upperhousing part or the lower housing part and the connecting means isguaranteed.

In another expedient refinement of the present invention, provision ismade for the lower housing part to have a two-part design featuring acarrier body to which the reflector is detachably connected and which isheld in its position relative to the upper housing part by theconnecting means. This allows easy replacement of the reflector withouthaving to detach the whole lower housing part from the connecting means.Because of this, first of all, time is saved when replacing a reflectoror the lamp and, secondly, material and thus cost are saved as well.

In a further advantageous embodiment of the present invention, provisionis made for the carrier body to have a tubular design. It is designed,for instance, as circular tube, rectangular tube, or oval tube, thecross-sectional area of the tube being shaped, in particular, as a curve(closed line) of second order. A tubular carrier body is very easy andinexpensive to manufacture and can moreover be easily connected to theconnecting means.

In a further advantageous refinement of the present invention, provisionis made for the carrier body to have a circular design. In this manner,it is also possible to provide a lamp for a fluorescent lamp having acircular shape. Because of this, the advantages described above can beoptimally used in the case of circular luminous element as well.

In another advantageous embodiment of the present invention, provisionis made for the housing to be formed in one piece. A housing of thatkind is easy to manufacture, and there is no risk for the lower housingpart or the upper housing part to unintentionally detach from theconnecting means, for example, because they where not properly connectedthereto. In this manner, the lamp is prevented from damage.

In a further advantageous refinement of the present invention, provisionis made for the at least one gap to run horizontally. This isparticularly advantageous in lamps which extend in a horizontal planebecause the gap can then be made especially long, thus resulting in aparticularly good air exchange between the interior space and theexternal space of the lamp.

In a further expedient refinement of the present invention, provision ismade for the at least one gap to be sized such that at least one of thereflectors fits through it. In this manner, it is very easy to replace areflector by simply pulling it out through the gap of the lamp andpushing a new reflector through the gap into the lamp.

In another expedient embodiment of the present invention, provision ismade for two gaps which are parallel to each other. In this manner, theair exchange between the interior space of the lamp and the externalspace is further improved so that the efficiency of the fluorescent lamp(inside the lamp) is further increased. It is preferred for the two gapsto be arranged on two opposing sides of the lamp. Because of this, anadvantageous aesthetic effect is achieved since the lamp has a symmetricdesign.

In a further advantageous embodiment of the present invention, provisionis made for the upper housing part to have a convex design with respectto the interior space of the housing. In this manner, a roof is formedwhich covers the luminous element and which prevents dirt which fallsdown from above from falling into the lamp. The dirt which falls downonto the upper housing part slides down outwardly along the curvature ofthe upper housing part toward the edge and finally falls off. Dirt whichdoes not fall off, such as dust, can be easily cleaned off because ofthe convex shape of the upper housing part since there are no edges orcorners which are difficult to access.

In another advantageous refinement of the present invention, provisionis made for the upper housing part to be transparent. Because of this,the entire light which is emitted and reflected upward reaches theceiling from where it is reflected into the room as stray lightproducing a very pleasant sensation. Thus, a very high efficiency isachieved for this indirect light.

In another expedient refinement of the present invention, provision ismade for a suspended lamp which is connectable to a ceiling using atleast one fastening element. It is preferred for the at least onefastening element to be a sheathed electric cable. Because of this, itis not required but possible to use a steel cable as a holder at whichthe lamp is suspended from the ceiling. Therefore, a lamp of that kindcan be installed in a particularly simple manner. This is achieved inthat a lamp which is produced according to one of the embodimentsdescribed above can have a very light design.

In a further expedient embodiment of the present invention, provision ismade for the at least one fastening element to be covered by a coveringhaving a concave shape with respect to the lamp, in particular, havingthe shape of a circular segment in a cross section. A canopy-likecovering of that kind has the advantage that the light emitted orreflected upward does not have any punctiform high luminances at theceiling but that a homogenous illuminance pattern is attained at theceiling because of the canopy-like covering. This results in a pleasantillumination by the indirect light which is scattered by the canopy-likecovering.

In a further advantageous refinement of the present invention, provisionis made for the lamp to be able to swivel about an axis parallel to theat least one gap. In this manner, it is possible to turn the lamp intosuch a position that the at least one gap is situated such that isconstitutes the lowest point of the lamp. As a result, foreign bodieswhich possibly have entered the interior space of the lamp fall out as,for example, flies which were attracted by the luminous element andwhich do not withstand the thermal stress due to the high temperature atthe lamp surface inside the lamp. Therefore, it is not necessary to takethe lamp apart to get out such foreign bodies therefrom.

In a further expedient refinement of the present invention, provision ismade for a luminous element to be arranged in the holding device of thelamp. It is preferred for the luminous element to be a fluorescent lamp,in particular, a high-intensity fluorescent lamp. In the case of arelatively small tube, a high luminance and thus good room illuminationare attained in this manner in connection with which the above describedadvantages of the depicted embodiments show to advantage particularlywell. In particular, a strong increase in efficiency is given comparedto known lamps featuring fluorescent lamps. Also given are a homogenousillumination by the indirect light and a good glare suppression of thedirect light. This glare suppression is necessary because modernfluorescent lamps have luminances of up to 30000 cd/m². When lookingdirectly into such a lamp, the perception of the eye is switched off fora short time so that black spots are seen before the eye during a shorttime. This is avoided via the glare suppression measures. Moreover, theluminance of the lamp and of the surfaces surrounding it is reduced insuch a manner that no excessive luminances occur in the visual field ofthe observer during work in front of a screen so that the observer doesnot perceive any glare.

Moreover, the objective is achieved by a method for cleaning theinterior space of a lamp which is designed according to one of theembodiments described above, the lamp being turned about the parallelaxis. The advantages attained by such a method are described above.

Furthermore, the objective is achieved by a method for illuminating aroom, using a lamp which is designed according to one of the abovedescribed embodiments and/or a reflector which is designed according toone of the above described embodiments. The advantages attained by sucha method are specified above in detail within the scope of thedescription of the reflector or of the lamp so that reference is madethereto at this point. In particular, the object is achieved by a methodfor illuminating a room in connection with which light is emitted by anilluminant, reflected by a reflector in the glare suppression region andfalls around the illuminant into the room to be illuminated. Using thismethod, in particular the efficiency of the illumination of a room isincreased because no light which penetrates into the glare suppressionregion is reflected back into the illuminant but, being guided aroundthe illuminant, rather is able to fall into the room to be illuminated.

Moreover, the object is achieved by a method for reducing the luminancein the direct light of a lamp in connection with which a partiallytransparent reflector which is designed according to one of theembodiments described above is brought into the radiation field, inparticular into the cone of radiation of the luminous element. Becauseof this, it is possible to look into the region from which light of thelamp is thrown out without being dazzled even in the case of luminouselements featuring a high luminance. However, the reduction of luminancein the direct light does not mean that thereby a smaller amount of lightexists the lamp but the light which does not pass through the partiallyreflector is perceived as indirect light which is scattered, forexample, via the ceiling. This gives rise to an optimum efficiency.

In a further embodiment of this method according to the presentinvention, provision is made for the degree of reduction in luminance tobe varied by inserting different partially transparent or transparentreflectors. In this manner, it is possible to respond to the individualrequirements of the room or to the personal preferences of the user ofthe lamp. Thus, it is possible, for instance, to reduce the luminance ofthe direct light to a greater degree if a lamp is concerned whichfrequently appears in the visual field of the user, for example, whenlooking at a screen, such as a lamp above a table. Equally, it ispossible to chose a lower reduction in direct luminance if the lamp isinstalled at a location where it hardly lies in the visual field of theuser as, for instance, behind a sofa, a cabinet or a partition wall.

In a further advantageous refinement of this method, provision is madefor the attained glare-suppression angle to be variable by insertingand/or moving different partially transparent or transparent reflectorswhich are designed according to one of the embodiments described above.Thus, the glare-suppression angle at which the direct light undergoesglare suppression can be adapted to the specific conditions of the roomor to the personal taste of the user through the selection of thereflector and/or the variation of the distance of the reflector from theilluminant. For instance, it is not necessary to provide a largeglare-suppression angle for lamp which is situated in a corner or niche.However, this may indeed be desired in the case of a lamp which islocated free in the room.

Furthermore, the object is achieved by using a partially transparentreflector which is designed according to one of the above describedembodiments for glare suppression of the direct light of a lamp. Withregard to the advantages, reference is made to the above explanations.

Moreover, the object is achieved by using a partially transparentreflector which is designed according to one of the above describedembodiments and for guiding the light which is emitted by a luminouselement of a lamp around the luminous element. With regard to theembodiment details of the partially transparent reflector and to theadvantages resulting from its use, reference is made to the aboveexplanations.

Furthermore, the object is achieved by using a lamp which is designedaccording to one of the embodiments described above for increasing theefficiency of the luminous element. With regard to the advantages andfurther details, reference is made to the above explanations. Furtherpreferred embodiments of the present invention will be depicted in thedrawings and explained in the figure description.

BRIEF DESCRIPTION OF THE INVENTION

FIG. 1 is a section through a first exemplary embodiment of a lampaccording to the present invention featuring a reflector according tothe present invention;

FIG. 2 is a perspective view of the first exemplary embodiment of FIG. 1of the lamp with the reflector;

FIG. 2 a is a partial perspective of the first exemplary embodiment ofFIG. 1 of the lamp with the luminous element but without the reflector;

FIG. 2 b is a partial perspective of the first exemplary embodiment ofFIG. 1 of the lamp with the reflector but without the luminous elementand the the upper housing part;

FIG. 2 c is a partial perspective of the first exemplary embodiment ofFIG. 1 of the lamp;

FIG. 3 is a view of the first exemplary embodiment of the lamp and ofthe reflector from the same direction as shown in FIG. 2, however,hidden edges are shown.

FIG. 4 shows a schematic section through the first exemplary embodimentfeaturing the optical path of individual light beams emitted by theluminous element;

FIG. 5 depicts a schematic section through a second exemplary embodimentof a lamp featuring a double-segmented upper housing part;

FIG. 6 represents a schematic section through a third exemplaryembodiment of a reflector with a luminous element;

FIG. 7 shows of a lamp featuring only a perspective view of the thirdexemplary embodiment of the reflector from FIG. 6;

FIG. 8 shows a section through a part of a fourth exemplary embodimentof a reflector;

FIG. 9 shows a section through a part of a fifth exemplary embodiment ofa reflector;

FIG. 10 depicts a section through a part of a sixth exemplary embodimentof a part of a reflector; and

FIG. 11 is a schematic, perspective view of a fourth exemplaryembodiment of a lamp in the form of a suspended lamp.

FIG. 12 is a partial cross section of the covering of the alternativeembodiment of the lamp shown in FIG. 11.

FIG. 13 is a partial plan view of an upper portion of the covering ofFIG. 12.

FIG. 14 is a partial plan view of an upper portion of the covering ofFIG. 12.

FIG. 15 is a partial perspective of an upper portion of the covering ofFIG. 12.

FIG. 1 shows a section through a lamp 24. Lamp 24 has a housing 3featuring an upper housing part 5 and a lower housing part 4. Upperhousing part 5 is connected to lower housing part 4 via a connectingmeans 10. Upper housing part 5 is arranged on connecting means 10 in aholding device 26. Holding device 26 has two U-shaped leg members 26 afeaturing pointed noses 19 formed on the inner sides thereof. Noses 19positively and frictionally engage with upper housing part 5, thusfirmly holding it in its position relative to connecting means 10. Lowerhousing part 4 is waved-shaped in cross-section and has a wave crest inits middle. This wave crest constitutes an axis of symmetry 25, thelower housing part being configured symmetrically thereto. The wavecrest rests on a tubular carrier body 6 which is connected to connectingmeans 10 via a bearing block 27 arranged on connecting means 10. Bearingblock 27 encircles tubular carrier body 6 in positive locking mannerover more than half its circumference. In this manner, carrier body 6 issecurely fixed in position relative to connecting means 10 and,consequently, also lower housing part 4 relative to connecting means 10.A reflector 8 in the form of double-segmented reflector having two wings8 a, 8 b which are arranged symmetrically to the axis of symmetry restson lower housing part 4 in a positive-locking manner. A knurled screw 28joins carrier body 6 to connecting means 10 and to lower housing part 4and to reflector 8. In this manner, a simple and secure connection amongthese parts and to upper housing part 5 is guaranteed. Reflector 8 has areflective surface 12 facing away from lower housing part 4. Thedescribed arrangement composed of upper housing part 5, connection means10 and lower housing part 4 defines an interior space 11 of lamp 24. Agap 7 is formed between upper housing part 5 and lower housing part 4and reflector 8, respectively. Arranged at connecting means 10 is aholding device 2 in the form of a lamp socket for a luminous element 1in which a luminous element 1 is located. Holding device 2 in the formof a lamp socket supplies luminous element 1 with power.

When luminous element 1 emits light, then the air in interior space 11of lamp 24 heats up. Gap 7 ensures air exchange with the external spaceso that the overtemperature in interior space 11 of lamp 24 does notrise by more than 5 degrees Celsius. The efficiency of a fluorescenttube strongly depends on the ambient temperature around luminous element1.

Since the temperature increases only imperceptibly, the efficiency whichis reduced by thermal effects drops by no more than 5% compared to afree luminous element 1, i.e. one that is not arranged inside a housing3. Lower housing part 4 has a transparent construction whereas reflector8 is designed such that it is partially transparent, that is, reflectivesurface 12 of reflector 8 lets through part of the light emitted byluminous element l; another part is reflected. The section throughreflective surfaces 12 is in each case a line of second order which ismade of continuously differentiable contour elements arranged side byside, in the simplest case, of circular segments or one circularsegment. In this connection, the radii of curvature of the respectivesegments of the partially transparent reflector are identical to thoseof lower housing part 4, except for the material thickness. Due to theshown design of reflector 8, it is achieved that the light emitted byluminous element 1 is not reflected back onto luminous element 1 but isguided past it, thus being used for illuminating the room in which lamp24 is located. In this manner, an optimum efficiency of lamp 24 isattained since none of the light beams which are emitted by luminouselement 1 is lost. The partially transparent construction of reflector 8permits glare suppression in the direct light. This is necessary becausemodern fluorescent lamps have luminances of up to 30000 cd/m². However,such high luminances are detrimental to the human eye and result infailure phenomena so that there is a necessity of glare suppression ofthe direct light. Therefore, the reduction in luminance via a partiallytransparent reflector 8 makes it possible for the user to look also intothe direct light of lamp 24 of the lamp without having to expect damageto his/her health. The two gaps 7 are so large that reflector 8 can beremoved from lamp 24 therethrough without difficulty. This permits easyreplacement of reflector 8. This is indicated, for example, if damagehas occurred to reflector 8 or if the user of lamp 24 would like useanother reflector 8 featuring a different partial light transmission, adifferent pattern, or a different color in lamp 24. On the other hand,the gap is so small that that when the reflector (without verificationof the assumption) is pushed from the right side, reflector strikesagainst stop nose 29 so that the gap resulting on the pushing side issmaller than a (VDE) finger so as to prevent contact with the lamp base.Alternatively, a stop ring 30 can be used in addition to stop nose 29.This stop ring prevents that the lamp base can be touched with a finger(as defined by the German Verband Deutscher Elektrotechniker) even whenreflector has been removed. Optionally, a locking screw (knurled screw)28 which is necessary (for rough operation) can be used forinterconnecting lower housing part 4 and/or carrier tube 6 and partiallytransparent sector 8 and/or carrier tube 6 and connecting part 10. Upperhousing part 5 has a completely transparent design so that the entirelight which is directly emitted by luminous element 1 penetrates throughupper housing part 5. The same applies to the indirect light reflectedby reflector 8. Because of this, the radiant intensity of the lightemitted or reflected upward is not reduced so that a uniform, pleasantilluminance is achieved over a large surface on the ceiling. The ceilingserves as a scattering body, and a good illumination of the room inwhich lamp 24 is located is achieved. Via noses 19 which can have apyramidshaped or also conical design, upper housing part 5 is connectedto U-shaped leg members 26 a of holding device 26, forming a positivelock. When inserting upper housing part 5 into holding device 26, thetips of noses 19 are deformed, resulting in a wedging of noses 19 inupper housing part 5, creating a frictional and positive lock. Thisconnection is extremely reliable, preventing unintentional detachment ofupper housing part 5 from holding device 26 and thus, from connectingmeans 10. In the following, equally acting element are provided withidentical reference symbols.

FIG. 2 depicts the first exemplary embodiment of lamp 24 known from FIG.1 in a perspective view. Lamp 24 (without luminous element 1) isessentially cylindrical, connecting elements 10 being arranged at theend faces of lamp 24. Gap 7 extends from one end of lamp 24 to theother, i.e., from the one connecting means 10 to the other connectingmeans 10. Upper housing part 5 is inserted into holding device 26 ofconnecting means 10 and is encircled by U-shaped leg member 26 a.Tubular carrier body 6 is supported in bearing block 27 of connectingmeans 10. Transparent lower housing part 4 is arranged on carrier body6. Reflector 8, which is visible through gap 7, rests on this lowerhousing part 4. Reflector 8 is drawn only in a small portion of lamp 24so that luminous element 1 arranged behind it in interior space 11 oflamp 24 is visible. In reality, reflector 8 extends over the wholelength of gap 7 from one end of lamp 24 to the other.

Here, knurled screw 28 connects carrier body 6 to lower housing part 4but not to reflector 8 so that reflector 8 can be removed from lamp 24and replaced with another reflector 8 through gap 7.

FIG. 3 depicts the first exemplary embodiment of lamp 24 from the sameperspective as in FIG. 2; however, the hidden edges are made visiblehere. In this manner, some details become discernible which will bediscussed in the following. The features described with reference toFIG. 2 b, will not be discussed again. Reflector 8 has two wings 8 a, 8b, as is already shown in FIG. 1, and rests on lower housing part 4essentially in a positive-locking manner. The described parts canoptionally be connected to each other using a fixing device such asknurl screw 28. Luminous element 1 is supported in holding device 2 inthe two connecting means 10 via which it is supplied with power. As inthe preceding and in the following Figures, the electrical supply lineis not shown since it is not different from conventional lamps 24 and,moreover, not essential to the present invention. It is well discerniblehow noses 19 at holding 26 engage with the ends of upper housing part 5which are inserted in fixing devices 26 of connecting means 10. Alsowell discernible is the U-shaped encircling of leg members 26 a aroundthe ends of upper housing part 5. Knurled screw 28 joins the same partsas in FIG. 2.

FIG. 4 schematically shows the optical path in a lamp 24 featuring apartially transparent reflector 8 as lower housing part 4 and atransparent upper housing part 5. The light emitted upward by lightingelement 1 is almost not reflected by transparent upper housing part 5.Thus, ceiling 21 generally existing above lamp 24 (see FIG. 11) isirradiated directly. The light which is emitted downward from luminouselement 1 impinges on partially transparent reflector 8 so that a partof the light beams is reflected by it. Reflector 8 is geometricallyconfigured in such a manner that the light it reflects does not impingeon luminous element 1 but is guided therearound. The light beams passingthrough reflector 8 are not shown for reasons of clarity. In order forreflector 8 to fulfil this specific light-guiding function, it is madeof two wings 8 a, 8 b which are formed symmetrically to axis of symmetry25. Here, axis of symmetry 25 runs in a direction perpendicular to thedrawing plane. In cross-section, each of wings 8 a, 8 b of reflector 8is formed as a curve of second order at its reflective surface 12, as aside-by-side arrangement of circular segments having a continuouslydifferentiable curve contour, preferably as a single circular segment.In this context, the center points of the radii of curvature or thecenter points of the circular segments lie in median planes passingthrough the axis of the luminous element. In the simplest case, this isa horizontal median plane E of luminous element 1. The relation betweendistance d of the virtual center points and the middle of luminouselement 1 to the respective radii of curvature varies in a range of from1:1 to 2:1. Via reflector 8, the direct component of the light emittedby luminous element 1 is reduced so that the glare of the direct lightis suppressed in angular range. Angle depends on how far reflector 8 isdrawn upward on its contour line (circular segment line). Moreover, FIG.4 clearly shows how gaps 7 are formed between reflector 8 and upperhousing part 5, through which a good air exchange between interior space11 of lamp 24 and the external space is possible. In this manner, it ispossible to attain the high efficiency of luminous element 1 alreadymentioned above.

FIG. 5 shows schematic representation of a further exemplary embodimentof a lamp 24 in which, compared to the exemplary embodiment of FIG. 4,transparent upper (monosegment) housing part 5 is substituted by adouble-segmented housing part 9. Along the lamp axis, the double segmentis designed symmetrically to the vertical plane passing through the lampaxis of luminous element 1. Double-segmented upper housing part 9 hasalso a transparent construction so that a nearly identical effect ensuesfor the beams transmitted by it as in the case of the monosegmenthousing part (except for the reflection and transmission data which arechanged according to the Fresnel equations); however, with a differentshape and visual appearance. Equal and equally acting parts are denotedby the same reference numerals as in FIG. 4. With regard to theirarrangement and mode of operation, reference is made to the descriptionof FIG. 4. It is also possible to replace transparent upper housing part5 by a second reflector 9. Then, second reflector 9 is constructed inthe same way as first reflector 8 and arranged in mirror symmetry tofirst reflector 8 with respect to horizontal median plane E of luminouselement 1. Second reflector 9 also has a partially transparentconstruction so that the same effect ensues for the beams reflected byit as that explained with respect to first reflector 8 in connectionwith FIG. 4. In this manner, a reduction in luminance in the directlight is attained both in the light of the luminous element emittedupward and in that emitted downward. This is particularly advantageousif lamp 24 is arranged in a room only at such a height that it can alsobe looked at from above. This is the case, for example, with a desk lamp24.

FIG. 6 shows a further exemplary embodiment of a lamp 24. To simplifythe representation, only luminous element 1 is depicted in its spatialrelationship to reflector 8 and to lower housing part 4. The embodimentof reflector 8 is identical to that shown in FIGS. 4 and 5 so that, withregard to the individual features, reference is made to the descriptionof these Figures. In this connection, reflector 8 rests on lower housingpart 4 essentially in a positive-locking manner. Only in the region ofaxis of symmetry 25, lower housing part 4 is rounded and thus, remainsat a distance under reflector 8. Lower housing part 4 has a transparentconstruction here as well whereas reflector 8 has a partiallytransparent surface 12 facing luminous element 1. The optical pathrepresenting the light emitted by luminous element 1 was dispensed withhere but it corresponds to that depicted with regard to reflector 8 inFIGS. 4 and 5.

FIG. 7 is a perspective view of the spatial design of reflector 8 andlower housing part 4 depicted in FIG. 6. In this connection, it is welldiscernible that surfaces 12 of reflector 8 which, in cross-section,have the shape of circular segments, as is shows in FIG. 6, eachcorrespond to a cylinder envelope in the three-dimensional embodiment.The two cylinder envelopes are abutted against each another along axisof symmetry 25. Using this design, the optical path shown in FIGS. 4 and5 is obtained in the reflected light along the entire length of tubularluminous element 1 so that the reflected light is not reflected byreflector 8 into luminous element 1 but guided around it. In thismanner, the high luminous efficacy described above is guaranteed alongthe entire length of luminous element 1.

FIG. 8 shows a further embodiment of a reflector 8. Here, a perforatedplate 18 is concerned which is made of a reflective material such asaluminum and which has holes 18 a and webs 18 b located therebetween.Reflector 8 is partially transparent since it reflects the light beamsimpinging on it from a luminous element 1 only at the locations at whichthere are webs 18 b between holes 18 a. If a light beam falls on one ofholes 18 a, then this light beam passes through reflector 8 in anunhindered manner. The degree of transparency of reflector 8 and thus,of its glare suppression characteristic through the reduction of theluminance perceived by the observer is determined by the relation of thearea of holes 18 a to the area of webs 18 b and the hole size itself.Such a reflector 8 in the form of a perforated plate 18 is very easy andinexpensive to manufacture, for example, by punching holes 18 a out ofan aluminum sheet. Thus, the buyer of a lamp 24 can chose the reflector8 which suits him and insert it into lamp 24, depending on the use oflamp 24 and the desired properties thereof.

FIG. 9 shows a further embodiment of a reflector 8. Reflector 8 has atransparent substructure 13 made, for example, of a transparent plasticsuch as Plexiglas. A reflective, perforated material 14 which can be,for example, metallic, is applied to transparent substructure 13 using ascreen-printing technique. This reflector 8 reflects light beams whichimpinge on reflective material 14. Here too, the degree of reduction inluminance attained by reflector 8 depends on the relation between thereflective area and the transmissive area and on the hole size. Thismeans here, that the degree of reduction in luminance can be adjusted bythe size of the area to which reflective material 14 is applied. Areflector 8 of that kind can be specially customized as well, andproduced in many different variants with regard to the reductions inluminance.

FIG. 10 depicts another exemplary embodiment of a reflector 8. Thisreflector 8 has a transparent substructure 13 as well. This transparentsubstructure 13 has bonded thereto a film 17 which features reflectiveregions 15 and transparent regions 16. With regard to the degree ofreduction in luminance and to the ease of manufacture or the response tocustomer wishes, the same applies as has already been explained abovewith regard to FIGS. 8 and 9.

FIG. 11 shows a further exemplary embodiment of a lamp 24. Here, asuspended lamp is concerned which is attached to a ceiling 21. Lamp 24is shown here only schematically, upper housing part 5 and lower housingpart 4 being depicted with gaps 7 situated therebetween. On the otherhand, neither connecting means 10 nor luminous element 1 are shown. Lamp24 is made so light that it is sufficient to suspend it from ceiling 21at two sheathed electric cables 20 conducting the electric current.There is not need to use steel cables for that purpose but these couldbe used in additionally or incorporated into the sheathed cable. Thefixing points of sheathed electric cables 20 at ceiling 21 are coveredby a covering 22. Covering 22 is designed as a canopy. The covering isconcave with respect to lamp 24 and extends parallel to the longitudinalextension of lamp 24. In cross-section, it has the shape of a circularsegment just as the cross-section of upper housing part 5. Thus, adesign in the form of a cylinder envelope segment ensues for covering22. Apart from the aesthetic effect that the fixing points of lamp 24 atceiling 21 are covered, such a covering 22 has also a positive effect onthe illumination of the whole room in which lamp 24 is located. Due tothe concave design with respect to lamp 24, no punctiform highluminances, so-called “luminance peaks” occur but a homogenous luminancedistribution ensues. Thus, the light beams in the light emitted orreflected upward which are scattered at covering 22 bring about auniform indirect illumination of the room which is pleasant for theobserver. The two points at which the two sheathed cables 20 exit lamp24 define an axis 23 running parallel to the two gaps 7. This axis 23running at the upper side of upper housing part 5 serves as a swivelaxis about which the whole lamp 24 can swivel. By turning lamp 24 aboutthis axis 23, it possible to swing lamp 24 into a position in which oneof the two gaps 7 forms the lowest point of lamp 24. Because of this,foreign bodies which possibly have accumulated in interior space 11 oflamp 24 fall out of lamp 24. Thus, an easy and inexpensive way isprovided for cleaning interior space 11 of lamp 24. This is necessary,for example, when flies have flown into interior space 11 of lamp 24and, there, are no longer able to fly due to the high thermal stress.This is particularly advantageous if lamp 24 is designed in two piecessince a lamp 24 having a one-part design cannot be taken apart intoupper housing part 5, lower housing part 4 and connecting means 10.

1. A lamp (24) comprising a holding device (2) for a luminous element(1) and a housing (3) which, at least partially, surrounds an interiorspace (11) provided for the luminous element (1), the housing (3)featuring an upper housing part (5) and a lower housing part (4),wherein a least one gap (7) exists between the upper housing part (5)and a lower housing part (4) through which air exchange is possiblebetween the interior space (11) of the lamp (24) surrounded by thehousing (3) and the external space, and further wherein the upperhousing part (5) features a fist reflector (9) and the lower housingpart (4) having a second reflector (8) which are each partiallytransparent.
 2. The lamp (24) as recited in claim 1, wherein the upperhousing part (5) and/or the lower housing part (4) are/is connected toconnecting means (10) in an easily detachable manner.
 3. The lamp (24)as recited in claim 2, wherein the connecting means (10) have noses (19)which frictionally and positively engage with the upper housing part (5)and with at least one of the lower housing part (4).
 4. The lamp (24) asrecited in claim 2, wherein the lower housing part (4) has a two-partdesign, featuring a carrier body (6) to which the reflector (8) isdetachably connected and which is held in its position relative to theupper housing part (5) by the connecting means (10).
 5. The lamp (24) asrecited in claim 4, wherein the lower housing part (4) and/or thereflector (8) are/is connected to the carrier body (6) and theconnecting means (10) via a simple knurled screw (28).
 6. The lamp (24)as recited in claim 4, wherein the at least one gap (7) runs(horizontally) parallel to the carrier body.
 7. The lamp (24) as recitedin claim 1, wherein the at least one gap (7) is sized such that at leastone of the reflectors (8, 9) fits through it.
 8. The tamp (24) asrecited in claim 1, wherein two gaps exist which are parallel to eachother.
 9. The lamp (24) as recited in claim 1, wherein the upper housingpart (5) has a convex design with respect to the interior space (11) ofthe housing (3).
 10. The lamp (24) as recited in claim 1, wherein theupper housing part (5) is transparent.
 11. The lamp (24) as recited inclaim 1, wherein the lamp is able to swivel about an axis (23) parallelto the at least one gap (7).